Relevance of Water/oil Interfacial Structure to Low Salinity Oil Recovery Process

This work aims at studying the origin of spontaneous emulsification occurring at the oil/water interface. This phenomenon was observed for the five crude oils tested as well as at the interface of an asphaltene toluene mixture and water. The kinetics of appearance of water micro-droplets was slowed down for increasing salt concentrations and the micro-droplet formation ceases when the chemical potential of water they contain is equal to the one of the water in the bulk solution. Nucleation events occur at the oil-water interface and at the solid surface/liquid interface: some water microdroplets are stuck together close to the oil/water interface, others grow in oil and sediment or nucleate at the oil/solid surface. This suggests the following mechanism: water molecules diffuse from the water reservoir into the oil phase, and then create droplets. These droplets are simultaneously fed by hydrosoluble "osmogeneous" species increasing the osmotic pressure, inducing an osmotic pumping of water molecules into micro-droplets WATER OIL

show abstract

“…The consequences of this phenomenon on oil recovery has been addressed in the proceeding of IOR 2019 35 .…”

Section: Resultsmentioning

confidence: 99%

Auto-Emulsification of Water at the Crude Oil/Water Interface: A Mechanism Driven by Osmotic Gradient

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Still, investigating the oil/water interfacial tension in the presence of salts within the aqueous phase is essential, when the role of fluid–fluid interactions has been increasingly highlighted by recent advances in new technologies of interface characterization. , Crude oil/water interfacial tension measurement is a primary tool to provide important information about the oil/water interface and the impact of several fluid–fluid interactions each of which would lead to LSE. A principal surface-active material within the crude oil phase has been reported to be asphaltenes that can diffuse into the oil/water interface and form a rigid solid-like interface. , Formation of a rigid interfacial film by asphaltenes at the oil/water interface has been recognised as the main mechanism of stable water in crude oil (W/O) emulsions.…”

Section: Introductionmentioning

confidence: 99%

Debunking the Impact of Salinity on Crude Oil/Water Interfacial Tension

2021

View full text Add to dashboard Cite

The salt content and composition of the water that is either produced with the oil or injected in an oil reservoir can change the composition of the oil at the oil/water interface. Having identified these compositional changes is key to designing the most optimized water ionic recipe to be used in waterflooding of an oil reservoir. Hence, there is a need to better understand the physicochemical interactions at the oil/water interface because of salinity effects. This study elucidates the effect of salinity on the interfacial interactions through pendant drop measurements of crude oil/water interfacial tension, surface charge evaluation by zeta potential, water content measurements by Karl Fischer titration, Fourier transform infrared (FT-IR), and ultraviolet–visible spectroscopy analyses. The interfacial tension results indicate that the interfacial tension increases with reduction in water salinity, which is shown for the first time by FT-IR and water content measurements to be proportional to the spontaneous formation of water microdispersion as the main mechanism of low salinity water injection. Formation of microdispersions and partitioning of surface-active materials by conjugated acidic compounds and/or acidic asphaltenes and low-molecular weight acidic compounds, respectively, are the main parameters controlling the crude oil/water interactions. Asphaltenes and acidic materials are shown to be the underlying compounds in the crude oil phase promoting the microdispersion formation.

show abstract

“…The possible role of crude oil and fluid–fluid interactions during LSWI in carbonate and sandstone reservoirs had been underestimated until microdispersion formation was introduced as the main responsible mechanism of LSWI . The microdispersion theory could support the extra oil recovery during LSWI regardless of rock type, which was a remarkable discovery for the oil and gas industry. , It was shown that microdispersions were water clusters surrounded with oil surface-active materials leading to wettability alteration through the detachment of surface-active materials from the rock surface; − this work was also supported by other researchers. , Several studies have been published in the literature reporting the formation of water microdispersion as the main mechanism of LSWI irrespective of different terminologies. ,− Other mechanisms were also introduced to attribute the additional oil recovery during LSWI to the fluid–fluid interaction, such as interfacial viscoelasticity variations and osmotic effects . Alvarado et al suggested that either increasing the sulfate content or decreasing the salinity of injection water would lead to incremental oil recovery through increasing the interfacial viscoelasticity.…”

Section: Introductionmentioning

confidence: 59%

Novel Insights into the Pore-Scale Mechanism of Low Salinity Water Injection and the Improvements on Oil Recovery

et al. 2020

View full text Add to dashboard Cite

The long-held industry view that the Low Salinity Effect (LSE) depends mainly on rock−fluid interactions has led to failures and successes that can be explained by fluid−fluid interactions. Therefore, elevating our knowledge about the microscopic interactions occurring in the crude oil/brine/rock system appears to be of paramount importance. This paper chooses to outline various analytical tools in combination with a microfluidic instrument (Micromodel) to identify these interactions at simulated reservoir conditions for the first time (temperature and pressure of 50 °C and 2000 psi). In this study, six crude oil samples have undergone testing for microdispersion quantification and surface charge evaluation. Microdispersion is a term referring to the spontaneous formation of water clusters (in micrometer sizes) within the crude oil during low salinity water injection (LSWI), which will be elaborated in this study. Despite all samples showing the same trend regarding the negative surface charges, they showed an entirely different propensity toward formation of water microdispersion. The analysis of the oil/water interface by Fourier-transform infrared spectroscopy (FT-IR) led to the understanding that conjugated acidic compounds within the crude oil are the main compounds for the creation of water microdispersions. The Micromodel results revealed the predominant role of microdispersions in oil swelling and wettability alteration in a porous medium leading to an increase in the microscopic sweeping efficiency, thus leading to improved oil recovery. Also highlighted is the pivotal importance of water microdispersion as a screening method for oil reservoirs before waterflooding operation.

show abstract

Relevance of Water/oil Interfacial Structure to Low Salinity Oil Recovery Process

Cited by 11 publications

References 0 publications

Auto-Emulsification of Water at the Crude Oil/Water Interface: A Mechanism Driven by Osmotic Gradient

Auto-Emulsification of Water at the Crude Oil/Water Interface: A Mechanism Driven by Osmotic Gradient

Debunking the Impact of Salinity on Crude Oil/Water Interfacial Tension

Novel Insights into the Pore-Scale Mechanism of Low Salinity Water Injection and the Improvements on Oil Recovery

Contact Info

Product

Resources

About